In a membrane fraction from 293 cells , the affinity of binding of ( 6R ) 5 methyltetrahydrofolate and a protein chimera composed of a protein fragment ( 1 92 ) from __SP__ __NODE__ protein and of a protein fragment ( 93 237 ) from __SP__ __NODE__ protein is greater than the affinity of binding of ( 6S ) 5 methyltetrahydrofolate and a protein chimera composed of a protein fragment ( 1 92 ) from __SP__ __NODE__ protein and of a protein fragment ( 93 237 ) from __SP__ __NODE__ protein .